1. Field of the Invention
This invention relates to a butt terminal of a two-part construction in which a pair of male and female terminals are butted to be electrically connected together.
2. Background
There are known various butt terminals including a pair of male and female terminals, in which opposed contacts are butted together, thereby making an electrical connection. One such example is disclosed in U.S. Pat. No. 4,591,222.
In the conventional butt 51, shown in FIG. 9, a socket-type female terminal 52 and a pin-type male terminal 53 are butted to be electrically connected together.
A front half portion of the female terminal 52 is defined by a cylindrical tubular portion 54, and a plurality of slits 55 are formed through a front end portion of the cylindrical tubular portion 54, and extend axially, so that a plurality of resilient arms 57, separated from one another by the slits 55, are formed. The cylindrical tubular portion 54 is tapering toward its front end into a diameter smaller than an outer diameter of the male terminal 53. The front end of the cylindrical tubular portion 54 is flaring to provide an introductory portion 56 for receiving the male terminal 53.
A cap-like push member 61 for being pushed by a front end of the male terminal 53 is mounted in a socket cavity 58 defined by the resilient arm 57, and is movable back and forth. A compression spring 62 is provide at a rear end of the push member 61.
A rear half portion of the female terminal 52 is defined by a rod-like body portion 60 having a wire connection hole 59 formed in a rear end thereof, and the cylindrical tubular portion 54 is secured to a front end of the body portion 60.
In the above conventional butt terminal 51, when the front end of the male terminal 53 is fitted into the introductory portion 56 at the front end of the female terminal 52, the resilient arms 57 are spread radially outwardly by the outer peripheral surface of the male terminal 53, and the front end of the male terminal 53 abuts against the push member 61. When the male terminal 53 is further inserted to completely compress the compression spring 62, the connection between the female and male terminals 52 and 53 is completed. The female and male terminals 52 and 53 are retained by retaining mechanisms (not shown) provided on their housings.
With respect to the electrically-connected condition, the contact between the front end of the male terminal 53 and the push member 61 is a surface-to-surface contact, and the contact between the push member 61 and the compression spring 62, as well as the contact between the compression spring 62 and the body portion 60, is generally a line contact.
Next, another butt terminal different in construction from the above butt terminal will be described. As shown in FIG. 11, in the butt terminal 71, a male terminal 73 is pushed to be connected to a female terminal 72 from the upper side, the female terminal 72 being formed by bending a strip of an electrically-conductive material into a generally Z-shape. In this condition, a spring portion 74 of the female terminal 72 is compressed, so that a proper contact pressure is maintained between the female terminal 72 and the male terminal 73. A wire W is connected to an end of a bottom portion 75 of the female terminal 72.
In the above conventional butt terminal 51 shown in FIG. 9, however, when the male terminal 53 is inserted obliquely into the female terminal 52, the compression spring 62 is compressed in a curved condition as shown in FIG. 10, and therefore only an lower portion in FIG. 10 is compressed while an upper portion is not compressed, thus inviting a problem that the electrical connection is affected.
The female terminal 52 includes the push member 61 and the compression spring 62 which are provided within the cylindrical tubular portion 54, which leads to a problem that the number of the component parts is large, and the cost is increased.
In the butt terminal 71 shown in FIG. 11, if the amount of fitting displacement with respect to the male terminal 73 is large, it is necessary to increase a length L of the bottom portion 72 and a radius K of the spring portion 74 so that an internal stress of the female terminal 72 can be kept to within a yield strength of the material, and in this case there arises a problem that the female terminal 72 can not be formed into a small size.
Another problem is that since the direction of extending of the wire W from the female terminal is perpendicular to the direction of fitting of the male terminal 73, the female terminal 72 can not be formed into a small size in this respect.